open-nomad/website/pages/docs/job-specification/group.mdx
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---
layout: docs
page_title: group Stanza - Job Specification
sidebar_title: group
description: |-
The "group" stanza defines a series of tasks that should be co-located on the
same Nomad client. Any task within a group will be placed on the same client.
---
# `group` Stanza
<Placement groups={['job', 'group']} />
The `group` stanza defines a series of tasks that should be co-located on the
same Nomad client. Any [task][] within a group will be placed on the same
client.
```hcl
job "docs" {
group "example" {
# ...
}
}
```
## `group` Parameters
- `constraint` <code>([Constraint][]: nil)</code> -
This can be provided multiple times to define additional constraints.
- `affinity` <code>([Affinity][]: nil)</code> - This can be provided
multiple times to define preferred placement criteria.
- `spread` <code>([Spread][spread]: nil)</code> - This can be provided
multiple times to define criteria for spreading allocations across a
node attribute or metadata. See the
[Nomad spread reference](/docs/job-specification/spread) for more details.
- `count` `(int: 1)` - Specifies the number of the task groups that should
be running under this group. This value must be non-negative.
- `ephemeral_disk` <code>([EphemeralDisk][]: nil)</code> - Specifies the
ephemeral disk requirements of the group. Ephemeral disks can be marked as
sticky and support live data migrations.
- `meta` <code>([Meta][]: nil)</code> - Specifies a key-value map that annotates
with user-defined metadata.
- `migrate` <code>([Migrate][]: nil)</code> - Specifies the group strategy for
migrating off of draining nodes. Only service jobs with a count greater than
1 support migrate stanzas.
- `reschedule` <code>([Reschedule][]: nil)</code> - Allows to specify a
rescheduling strategy. Nomad will then attempt to schedule the task on another
node if any of the group allocation statuses become "failed".
- `restart` <code>([Restart][]: nil)</code> - Specifies the restart policy for
all tasks in this group. If omitted, a default policy exists for each job
type, which can be found in the [restart stanza documentation][restart].
- `shutdown_delay` `(string: "0s")` - Specifies the duration to wait when
stopping a group's tasks. The delay occurs between Consul deregistration
and sending each task a shutdown signal. Ideally, services would fail
healthchecks once they receive a shutdown signal. Alternatively
`shutdown_delay` may be set to give in flight requests time to complete
before shutting down. A group level `shutdown_delay` will run regardless
if there are any defined group services. In addition, tasks may have their
own [`shutdown_delay`](/docs/job-specification/task#shutdown_delay)
which waits between deregistering task services and stopping the task.
- `task` <code>([Task][]: &lt;required&gt;)</code> - Specifies one or more tasks to run
within this group. This can be specified multiple times, to add a task as part
of the group.
- `vault` <code>([Vault][]: nil)</code> - Specifies the set of Vault policies
required by all tasks in this group. Overrides a `vault` block set at the
`job` level.
- `volume` <code>([Volume][]: nil)</code> - Specifies the volumes that are
required by tasks within the group.
## `group` Examples
The following examples only show the `group` stanzas. Remember that the
`group` stanza is only valid in the placements listed above.
### Specifying Count
This example specifies that 5 instances of the tasks within this group should be
running:
```hcl
group "example" {
count = 5
}
```
### Tasks with Constraint
This example shows two abbreviated tasks with a constraint on the group. This
will restrict the tasks to 64-bit operating systems.
```hcl
group "example" {
constraint {
attribute = "${attr.cpu.arch}"
value = "amd64"
}
task "cache" {
# ...
}
task "server" {
# ...
}
}
```
### Metadata
This example show arbitrary user-defined metadata on the group:
```hcl
group "example" {
meta {
"my-key" = "my-value"
}
}
```
[task]: /docs/job-specification/task 'Nomad task Job Specification'
[job]: /docs/job-specification/job 'Nomad job Job Specification'
[constraint]: /docs/job-specification/constraint 'Nomad constraint Job Specification'
[spread]: /docs/job-specification/spread 'Nomad spread Job Specification'
[affinity]: /docs/job-specification/affinity 'Nomad affinity Job Specification'
[ephemeraldisk]: /docs/job-specification/ephemeral_disk 'Nomad ephemeral_disk Job Specification'
[meta]: /docs/job-specification/meta 'Nomad meta Job Specification'
[migrate]: /docs/job-specification/migrate 'Nomad migrate Job Specification'
[reschedule]: /docs/job-specification/reschedule 'Nomad reschedule Job Specification'
[restart]: /docs/job-specification/restart 'Nomad restart Job Specification'
[vault]: /docs/job-specification/vault 'Nomad vault Job Specification'
[volume]: /docs/job-specification/volume 'Nomad volume Job Specification'